I purchased a cabinet door direct from the factory, so yes, it can be done. There are, however, a couple problems.
1. sources for various items can change at any time during production. For example, at some point Coachmen stopped putting retractable kitchen faucets in and started installing "regular" faucets. It would be impossible to obtain the previous model, since it is no longer available.
2. their prices can be amazingly high. Things you'd think would be very expensive are dirt cheap, while other items you'd expect to be very inexpensive are not.
3. parts purchased from the factory are pulled from the production line, so there is no telling how long you'll have to wait to get your part/accessory.
Lowe's or Home Depot have lots to choose from, and prices are low enough that if you can't match exactly what is already there, you can simply replace everything with higher quality hardware, too.
2014 Coachmen Catalina 253RKS
2016 Keystone Summerland Mini 1750RD
2012 F250 Lariat 6.2L Crew Cab FX4
Reese dual cam SC/WDH